1. Field of the Invention
The present invention relates generally to automatic spray dispensers for releasing pressurized contents from an attached pressurized reservoir, and more particularly to pneumatic timed spray dispensers which use as their sole energy source the pressure contained in the pressurized reservoir.
2. Prior Art
The most effective method of using some products, such as insecticides and air fresheners, is to spray quantities of the product into the atmosphere at regular intervals. In practice these regular intervals are difficult to achieve with the manual valves generally supplied with the reservoir. They a difficult time maintaining a regular schedule of spraying. A better way to ensure regular dispersals of the product is to attach a spray dispenser to the reservoir which will automatically periodically release the product. Once the automatic spray dispenser is attached to the reservoir, the reservoir may then be placed in an advantageous location, such as near the ceiling or in an attic or basement. Once properly positioned, it can be allowed to operate unattended. This ensures the product will get where it is needed, when it is needed.
An automatic spray dispenser that is simple in construction effective in dispersing at regular intervals a fixed quantity of product, and easy to manufacture would be highly desirable. Unfortunately, dispensers that use electronic timers and valves are expensive and require an electrical current source. Heretofore, dispensers which use reservoir pressure as their sole energy source have had problems. More particularly, many such dispensers were complex in design and difficult to manufacture. Another problem experienced with certain automatic timed spray dispensers which utilize the container pressure as the sole motive force is their inability to discharge substantially all of their contents. Still another problem of prior art spray dispensers has been their inability to maintain a substantially constant time interval between discharge. These problems resulted from the manner in which the container pressure was utilized to dispense the pressurized contents. One solution to this problem is disclosed in U.S. Pat. No. 5,025,962 assigned to one of the co-inventors herein. The dispenser disclosed in that patent utilized a timing piston contraction that maintained a constant pressure differential on opposing sides of the timing piston. Although this design solved certain prior art problems the resultant discharged contents were not sufficiently atomized due to separation of the propellant and the active fluid in the pressurized container. When not properly atomized, the active ingredients form droplets which immediately fall wasted to the floor, rather than forming the fine mist required for the product to be carried by the air and properly dispensed.